Seasonal variation in trawl codend selection of northern North Sea haddock   总被引：1，自引：0，他引：1  

Ozbilgin  H.; Ferro  R.S.T.; Robertson  J.H.B.; Holtrop  G.; Kynoch  R.J. 《ICES Journal of Marine Science》2006,63(4):737-748

  相似文献   

中国马尾藻属的研究Ⅲ.丛伞托序族     

曾呈奎  陆保仁 《海洋与湖沼》1994,25(3):266-272

对中国马尾藻属，真马尾藻亚属，滑托组，丛伞托序族的种类进行系统研究。此族种类的主要特征是生殖托光滑，聚伞状排列在小校上，生殖托柄状部位都有生殖窝。多孢马尾藻是该族的非常特殊种类，它的分校和小分枝上密生刺和羽状分裂的藻叶。文中还报道了一个新种一长干马尾藻。模式标本产自广东省徐闻，还见于海丰。至今为止，丛伞托序族在中国共有两种。  相似文献   

Lagrangian measurements in the Kamchatka Current and Oyashio     

P. J. Stabeno  R. K. Reed  J. E. Overland 《Journal of Oceanography》1994,50(6):653-662

From 1988 to 1993, 23 satellite-tracked drifting buoys entered the Kamchatka Current. The buoy trajectories showed a well-formed, high-speed current that originated near Shirshov Ridge, and flowed southward through Kamchatka Strait. During some years, the buoys turned eastward at 50°N, while in other years they were transported as far south as Japan (40°N). Only one buoy entered the Sea of Okhotsk. Eddies were evident in many of the buoy trajectories. Greatest maximum daily velocities (>100 cm s^–1) were observed south of Kamchatka Strait, with 50–60 cm s^–1 being more common.  相似文献   

Interannual to diurnal variability in the near-surface scattering layer in Drake Passage     

Chereskin  T. K.; Tarling  G. A. 《ICES Journal of Marine Science》2007,64(9):1617-1626

  相似文献   

Tank wall effects on broadside current forces on barge models     

S.K. Chakrabarti  D.C. Cotter 《Ocean Engineering》1994,21(5)

Three different barge sizes were tested in uniform current in a tank of limited width. One of the barges was tested with and without bilge keels. Tests were conducted in both deep and shallow water. The barges were placed broadside to the current flow and the lateral forces on the barges were measured. The effect of the tank walls on these forces is clearly shown.  相似文献   

Caught in the act: the 20 December 2001 gravity flow event in Monterey Canyon     

C. K. Paull  W. Ussler  H. G. Greene  R. Keaten  P. Mitts  J. Barry 《Geo-Marine Letters》2003,22(4):227-232

A sediment gravity flow descended through the axis of Monterey Canyon on 20 December 2001 at 13:35 Pacific standard time. The timing of this event is documented by a current-meter package which recorded an 11.9-dbar pressure increase in less than 10 min and was found 550 m down-canyon from its deployment site, buried completely within a >70-cm-thick gravity flow deposit. This event is believed to have started in less than 290 m of water because an instrument at this location was also lost at the same time. A 178-cm core collected after the event from the axis of the canyon at 1,297-m water depth contained fresh, greenish, chlorophyll-rich organic material at 32-cm sub-bottom depth, suggesting the event extended to this water depth. The only trigger identified for this mass movement event appears to be moderate sea and surf conditions. Thus, gravity flow events of this magnitude do not require an exceptional triggering event.  相似文献   

Molecular identification of bloom-forming species Phaeocystis globosa(Prymnesiophyta)and its dispersal based on rDNA ITS sequence analysis   总被引：3，自引：1，他引：3  

Chen Yueqin  Shao Peng  Wang Ning  Zhou Hui  Qu Lianghu  Linda K. Medlin 《海洋学报(英文版)》2003,22(2)

Abstract-The colony-forming Phaeocystis species are causative agents of dense bloom occurrences incoastal waters worldwide. It is difficult to separate them because of the different morphologies associatedwith their colonial stages. In this study we applied molecular approaches to analyze the genetic variationof Phaeocystis globosa and Phaeocystis pouchetii from several geogrtaphic regions, and to assist in tracingthe dispersal of bloom-forming Phaeocystis species in coastal waters of China. The Sequences of the inter-nal transcribed sacers (ITS1 and ITS2) of rDNA and the 5.8S ribosomal RNA gene of Phaeocystisstrains were determined. Sequence comparison shows that P.globosa was the most divergent toP. pouchetii, exhibiting sequence divergence higher than 0.08. However, lower genetic divergences ex-isted between strains of P.globosa. The sequence comparison of the Phaeocystis rDNA ITS clearlyshows that the species isolated from the southeast coast of China is identified as P. globosa rather thanP. cf. po  相似文献   

A phase-averaged Boussinesq model with effective description of carrier wave group and associated long wave evolution     

K. Nadaoka  K. Raveenthiran 《Ocean Engineering》2002,29(1):21-37

From the phase-resolving improved Boussinesq equations (Beji and Nadaoka, Ocean Engineering 23 (1996) 691), a phase-averaged Boussinesq model for water waves is derived by more effectively describing carrier wave groups and accompanying long wave evolution with less CPU time. Linear shoaling characteristics of carrier wave equations are investigated and found to agree exactly with the analytical expression obtained from the constancy of energy flux for the improved Boussinesq equations themselves, showing that the present model equations are the results of a consistent derivation procedure regarding energy considerations. Numerical simulations of the derived equations for the single wave group and narrow-banded random waves show the validity of the present model and its high performance, especially on the CPU time.  相似文献   

Caught in the act: the 20 December 2001 gravity flow event in Monterey Canyon     

C. K. Paull  W. Ussler  H. G. Greene  R. Keaten  P. Mitts  J. Barry 《Geo-Marine Letters》2002,22(4):227-232

A sediment gravity flow descended through the axis of Monterey Canyon on 20 December 2001 at 13:35 Pacific standard time. The timing of this event is documented by a current-meter package which recorded an 11.9-dbar pressure increase in less than 10 min and was found 550 m down-canyon from its deployment site, buried completely within a >70-cm-thick gravity flow deposit. This event is believed to have started in less than 290 m of water because an instrument at this location was also lost at the same time. A 178-cm core collected after the event from the axis of the canyon at 1,297-m water depth contained fresh, greenish, chlorophyll-rich organic material at 32-cm sub-bottom depth, suggesting the event extended to this water depth. The only trigger identified for this mass movement event appears to be moderate sea and surf conditions. Thus, gravity flow events of this magnitude do not require an exceptional triggering event.  相似文献   

Second-order drift force response of offshore guyed towers     

R. S. Bisht  A. K. Jain 《Ocean Engineering》1995,22(3)

An iterative frequency domain method of analysis is presented for determining the response behaviour of Guyed Offshore Towers to low-frequency, second-order wave drift forces generated in a random sea environment. For the response analysis, the tower is idealized as a shear beam with a rotational spring at the bottom support. The guylines are replaced by a non-linear spring. The second-order drift force is considered to be proportional to the square of the wave elevation and is simulated using a drift force coefficient and the time history of a slowly varying wave envelope in random sea. The responses due to drift forces are obtained in frequency domain by incorporating the non-linearities produced due to non-linear guy lines. An example problem is solved under different random sea states to compare the response behaviour of the tower obtained by the second-order wave force, the first-order wave force and a combination of the two.  相似文献